Network Working Group R. Hinden
Request for Comments: 1897 Ipsilon Networks
Category: Experimental J. Postel
ISI
January 1996
IPv6 Testing Address Allocation
Status of this Memo
This document specifies an Experimental protocol for the Internet
community. This memo does not specify an Internet standard of any
kind. Discussion and suggestions for improvement are requested.
Distribution of this memo is unlimited.
1.0 Introduction
This document describes an allocation plan for IPv6 addresses to be
used in testing IPv6 prototype software. These addresses are
temporary and will be reclaimed in the future. Any IPv6 system using
these addresses will have to renumber at some time in the future.
These addresses will not to be routable in the Internet other than
for IPv6 testing.
The addresses described in this document are consistent with the IPv6
Addressing Architecture [ARCH]. They may be assigned to nodes
manually, with IPv6 Auto Address Allocation [AUTO], or with DHCP for
IPv6 [DHCPv6].
Hinden & Postel Experimental [Page 1]RFC 1897 IPv6 Testing Address Allocation January 1996
2.0 Address Format
The address format for the IPv6 test address is consistent with the
provider-based unicast address allocation [PRVD] which is as follows:
| 3 | 5 bits | 16 bits | 8 | 24 bits | 8 | 64 bits |
+---+----------+----------+---+------------+---+----------------+
|010|RegistryID|ProviderID|RES|SubscriberID|RES|Intra-Subscriber|
+---+----------+----------+---+------------+---+----------------+
The specific allocation of each field of the test address format is
as follows:
| 3 | 5 bits | 16 bits | 8 | 24 bits | 8 | 16 bits|48 bits|
+---+----------+----------+---+------------+---+--------+-------+
| | |Autonomous| | IPv4 | | Subnet | Intf. |
|010| 11111 | System |RES| Network |RES| | |
| | | Number | | Address | | Address| ID |
+---+----------+----------+---+------------+---+--------+-------+
where:
010
This is the Format Prefix used to identify provider-based
unicast addresses.
11111
This is a Registry ID reserved by the IANA. The initial use of
addresses in this Registry ID for IPv6 testing is temporary.
All users of these addresses will be required to renumber at
some time in the future.
Autonomous System Number
This is the current autonomous system number assigned to the
provider providing internet service to the an IPv6 testers
organization. For example for IPv6 testers receiving internet
service from BBN Barrnet would use autonomous system number 189.
This would be coded in the autonomous system field of the
address as follows:
0000 0000 1011 1101 (binary)
Hinden & Postel Experimental [Page 2]RFC 1897 IPv6 Testing Address Allocation January 1996
The values for the autonomous system number of an organization's
provider can be obtained from that provider, or can be looked up
in the "whois" database maintained by the internic.net.
RES
This field is reserved and must be set to zero.
IPv4 Network Address
This is based on the current IPv4 routable address for the
subscriber which the interface is connected. It is formed by
taking the high order 24 bits of the IPv4 address. For example
for an IPv4 address (in IPv4 syntax):
IPv4 Address
------------
39.11.22.1
the value to put in this field of IPv6 address is:
IPv4 Format Hex
------------ ------
39.11.22 270B16
This technique for generating values for this field only works
for subscribers which have IPv4 subscriber prefixes less than
equal to 24 bits long. There may be subscribers using IPv4
addresses with longer subscriber prefixes, but this conflict is
expected to be very rare. Subscribers with subscriber prefixes
larger than 24 bits should use the remaining bits in the IPv4
prefix as the high order bits in the Subnet Address field.
RES
This field is reserved and must be set to zero.
Subnet Address
The Subnet ID identifies a specific physical link on which the
interface is located. There can be multiple subnets on the same
physical link. A specific subnet can not span multiple physical